In most toilets a flush tank is mounted on top of the bowl behind the seat. A flush crank arm is attached outside the front or side wall of the tank to a shaft which extends into the tank through an opening in the tank wall. This shaft actuates the toilet flush mechanism inside the tank when the crank arm outside the tank is manually cranked downward through a small arc to turn the shaft.
A toilet seat which covers all or part of a toilet bowl rim is attached behind the rim of the bowl by a hinge at the rear of the seat. The seat can be raised and lowered on its hinge between a stable horizontal position, at which the seat rests on the rim of the bowl, and a stable upright position just beyond vertical, at which the seat leans back against the tank. Usually a seat cover is similarly hinged and can be similarly raised and lowered. As the seat is swung forward from its stable upright position, it passes the vertical plane of the hinge whence the seat can drop freely by its own weight to its stable horizontal position, at which it is used as a seat.
My invention is a mechanism for lowering the toilet seat by pushing the seat slightly forward from its stable upright position, just enough so that the seat can drop by its own weight as described. The force for pushing the seat forward derives from manual cranking of the flush crank arm. When the crank arm is pushed down to flush the toilet, the seat is pushed forward and drops to its horizontal position on the toilet bowl rim.
One advantage of my invention is that the entire mechanism is outside the tank. In U.S. Pat. No. 5,222,260, a push pin was actuated, through mechanical linkage by a hydraulic drive inside the tank, causing the push pin to push the seat forward from the stable upright position to a point where it could fall by its own weight. That required permanently elevating the tank lid for access of the linkage to the inside of the tank.
Another advantage of my invention is that it requires no change in the existing structure of the toilet. In U.S. Pat. No. 5,060,318 the seat was lowered by a spring-assisted hinge mechanism. A trip wire was connected at one of its ends to the flush handle on the tank and at its other end to a push bar in contact with a shaft member of the seat hinge. When the flush handle was turned, the trip wire pushed against a pusher bar on the shaft member causing the shaft member of the hinge to turn enough to move the seat forward to a point where the seat would drop. That mechanism required a special hinge and shaft mechanism not available on ordinary toilets.